<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
<HTML>
<HEAD>
<TITLE>80386 Programmer's Reference Manual -- Opcode PUSHA</TITLE>
</HEAD>
<BODY STYLE="width:80ch">
<B>up:</B> <A HREF="c17.htm">
Chapter 17 -- 80386 Instruction Set</A><BR>
<B>prev:</B><A HREF="PUSH.htm"> PUSH Push Operand onto the Stack</A><BR>
<B>next:</B><A HREF="PUSHF.htm"> PUSHF/PUSHFD Push Flags Register onto the Stack</A>
<P>
<HR>
<P>
<H1>PUSHA/PUSHAD -- Push all General Registers</H1>

<PRE>
Opcode  Instruction  Clocks   Description

60      PUSHA        18       Push AX, CX, DX, BX, original SP, BP, SI, and
                              DI
60      PUSHAD       18       Push EAX, ECX, EDX, EBX, original ESP, EBP,
                              ESI, and EDI
</PRE>


<H2>Operation</H2>

<PRE>
IF OperandSize = 16 (* PUSHA instruction *)
THEN
   Temp := (SP);
   Push(AX);
   Push(CX);
   Push(DX);
   Push(BX);
   Push(Temp);
   Push(BP);
   Push(SI);
   Push(DI);
ELSE (* OperandSize = 32, PUSHAD instruction *)
   Temp := (ESP);
   Push(EAX);
   Push(ECX);
   Push(EDX);
   Push(EBX);
   Push(Temp);
   Push(EBP);
   Push(ESI);
   Push(EDI);
FI;
</PRE>

<H2>Description</H2>

PUSHA and PUSHAD save the 16-bit or 32-bit general registers,
respectively, on the 80386 stack. PUSHA decrements the stack pointer
(SP) by 16 to hold the eight word values. PUSHAD decrements the
stack pointer (ESP) by 32 to hold the eight doubleword values. Because
the registers are pushed onto the stack in the order in which they were
given, they appear in the 16 or 32 new stack bytes in reverse order. The
last register pushed is DI or EDI.

<H2>Flags Affected</H2>

None

<H2>Protected Mode Exceptions</H2>

#SS(0) if the starting or ending stack address is outside the stack segment
limit; #PF(fault-code) for a page fault

<H2>Real Address Mode Exceptions</H2>

Before executing PUSHA or PUSHAD, the 80386 shuts down if SP or
ESP equals 1, 3, or 5; if SP or ESP equals 7, 9, 11, 13, or 15, exception
13 occurs

<H2>Virtual 8086 Mode Exceptions</H2>

Same exceptions as in real-address mode; #PF(fault-code) for a page
fault


<P>
<HR>
<P>
<B>up:</B> <A HREF="c17.htm">
Chapter 17 -- 80386 Instruction Set</A><BR>
<B>prev:</B><A HREF="PUSH.htm"> PUSH Push Operand onto the Stack</A><BR>
<B>next:</B><A HREF="PUSHF.htm"> PUSHF/PUSHFD Push Flags Register onto the Stack</A>
</BODY>
